Filter.



E. J; SWEETLAND.

FILTER. APPLICATION FILED MAY 9,1914- Patented Sept. 18,1917.

M ATTONEY agent present in 'use of fine wire netting or nnrrnn snares.

PATENT @FFEQE.

FILT R.

Specification of Letters Patent.

Patented Sept. is, rare.

Application filed May 9, 1914. Serial No. 837,379.

To all whom it may concern:

a citizen of the United States, residing in the town of Montclair,county of Essex, and

State of New Jersey, have invented certain new and useful Improvementsin Filters, of which the following is a specification.

My invention relates to a filter medium composed of metallic fibersaggregated into sheets. Hitherto the filter medium most used has been ofcloth and for many purposes this is entirely satisfactory. However, whenthe substance to be filtered contains an agent whichis destructive ofcloth, such for instance as strong alkalis, the cloth filter medium israpidly destroyed and its replacement not only represents a considerablewaste in time during which the filter is thrown out of service, but alsoentails a large financial expenditure. The object of my invention is toprovide a filter medium which may be used to replace cloth as a filtermedium, and which will be composed of a material which is preservedrather than attacked by the alkali or other destructive the liquid to befiltered.

In my improved filter structure I provide a filter medium which iscomposed of matted metallic filaments. These filaments when composed ofsteel or lead are known in the trade as steel wool or lead wool. Thereare many ways in which they may be aggregated to form a suitablefiltering medium, and certain preferred structures will be described indetail below. I am aware that in the filtration of acid solutions glasswool and so-called mineral wool, formed of slag, have heretofore beenutilized, but neither of these substances is adaptable to the purpose ofmy invention, lacking many of the advantages which are inherent in ametallic structure. I. am also aware that the screen has been proposed,but it will be obvious that this material neither filters in the samemanner as that of the present invention, nor does it possess themanifold advantages attached to my improved filter medium.

In the accompanying drawings which form a part of this specification,Figure 1 is a vertical sectional view of a portion of a leaf-filtershowing three of the filterleaves; Fig. 2 is a transverse sectional viewon a vertical plane at right angles to tbat' of Fig. 1, parts beingbroken away to show the internal construction of the leaf; Fig. 3 is anenlarged detail fragmentary sectional view through a portion of a leaf;Fig. -l-. is an elevation of one type of fabric adapted to be used asthe filter medium; Fig. 5 is a sectional view of this medium; Fig. 6 isan enlarged sectional view of a portion of a filter-leaf taken on aplane at right angles to that of Fig. 3; Fig. 7 is a view similar toFig. 6 but illustrating a modification; Fig. 8 is a vertical sectionalView of a plate and frame filter; Fig. 9 is .a sectional view on lineIX-IX of Fig. 8; Fig. 10 is a sectional view on line X-X of Fig. 9; Fig.11 is a I sectional view similar to Fig. 8 but showing a modified formof filter; Fig. 12 is a sectional view on line XII-XII of Fig. 11; Fig.13 is a view similar to Fig. 4 showing a modified type of fabric; andFig. 14. is a sectional view of this fabric.

Referring to the drawings in detail, the numeral 1 designates the shellof a filter in which is mounted a plurality of filter-leaves 2. Eachleaf comprises an outer hoop of channel section having the flanges orlegs 1- and 5'pr0jecting radially inward. Adjaeent to the flange at andretained in place thereby is a circular disk 6 of wire screen. Adjacentto the 'flange 5 and retained in place thereby is a similar circulardisk 7. Centrally mounted between the flanges of the channel is acircular disk 8 of coarse screen, a portion of which enters between thedepending walls 9 of the outlet nipple 10, which is suspended from theshell as shown in Fig. 1 and which communicates with the outlet manifold11 through the pipe 12.

Between the disks 6 and 8, and also between the disks 7 and 8, ismounted a layer of filter medium 13. This filter medium may comprise awoven fabric, one set of threads of which is composed of wires 14, andthe other threads of which are formed of strands 15 of aggregatedmetallic filaments such as steel wool or lead wool of commerce. Thesestrands, as clearly indicated in Figs. 4 and 5, consist of aggregatedfilaments arranged in the same general direction but overlapping oneanother, and owing to their inherent nature being irregular in theirarrangement, so as to force the filtrate to take a devious course inpasing through the fabric. Such a filter as I have described,particularly when formed of steel wool, is not ailected by alkalinesolutions such as caustic soda or potash, but is preserved thereby.Furthermore, this fabric possesses a consi erabledegree of i e orresilience, and when, after considerable use, it may have become cloggedwith the matter filtered out by it,.it maybe removed from the filter andsubjected to a beating, which will free the included foreign matter andat the same time result in no disadvantageous effect upon the fabricbecause of this prop- The filter fabric requires this treatment only atintervals of several weeks in the case of average filtration conditions.In normal operation the cake forming on the filter me dium is removed bythe process which is known as reversing the flow. This is accomplishedby forcing clear water underlodges the cake, causing it to fall bygravity.

into the bottom of the shell, whence it may be removed in any convenientmanner. Consequently only a small proportion of the solid removed fromthe filtrate reaches the interior of the filter medium in such a way asto be so intimately associated therewith that the reversal of flow willnot remove it.

With my improved filter medium this, too,

may be readily dislodged by whipping or beating and the filter mediumthereby restored to its original state.

Another important advantage of my improved filt'er medium lies in thefact that in reversing the flow, as above described, the pressure of theclear water is exerted very evenly over the entire area of the cakewhich it is desired-to dislodge, which results in the removal of theentire cake. With some other filter fabrics, such as the fine wirescreen sometimes employed, the weakest part of the cake breaks awayfirst, and the screen itself presents so little opposition to thepassage of the clear water, that this water rushes through the aperturethus formed in the cake,and the pressure is so dissipated that theremainder of the cake is not dislodged. Of course steam or air underpres sure may be used in place of water.

In the construction of the fabric, 1 find it most convenient to use thestrands of metallic wool as the weft threads and the wires as the warp,although in some cases thisorder may be reversed. After this filterfabric has been woven, I find it extremely advantageous to pass itthrough powerful rolls which will flatten the outstanding filaments andmold the entire fabric into one closely matted whole, as indicated inFigsj l and 5.

In some instances I find it possible to do away with the outer retainingscreens 6 and 7 The filter which has already been described is similarin its general construction, with the exception of the specific filtermedium, to the type of filter shown and described in detail in my PatentNo. 1,083,305,

dated January 6, 1914. The course of the filtrate, as will be obvious,will be through the screens 6 and 7, thence passing through the filtermedium 13. The clear filtrate then enters the space between the disks 13and passes up through the interstices of the coarse spacing screen 8into the nipple 10, and thence into the outlet manifold.

Fig. 7 illustrates a modification in which the fabric 13 is supplantedby a mat 16 of the metallic wool or similar substance heretoforedescribed. In this case the wool is aggregated into sheets andpreferably rolled to a substantially uniform thickness, and occupiesthe: same position in the filterleaf as the fabric 13 in the structureabove described. Furthermore, in some cases it may be desirable to formboth the warp and the weft of the metallic filaments or me tallic woolshown in Figs. 13 and 14:, in which the numeral 17 designates the warpand the numeral 18 the weft. Such a strucbers'in this case is composedof a coarse.

central screen 19, on each side of which is a finer screen 20. Next tothese screens 20 is a layer 21 of the fabric described in connecby theouter screens 22, which in turn are supported by the rectangularretaining -'tion with Fig. 7, which is retained in place plates 23secured to the body of the filter. A

passage 24 leads from the space between the lavers of filtering material21 to the outlet manifold 25. V A

In Figs. 11 and 12 I have illustrated a further modification showinganother well- I known type of filter, in which the spaces '26, intowhich the material to be filtered passes, are formed by the shoulders 27extending fromthe filter plates and taking the place of the spacingmembers 28 in the filter of Figs. 8,9 and 10. The construction,

of the filter members in this case is otherwise identical with thatalready described.

While I have illustrated only certain specific embodiments of myinvention, I realize 1 that it is susceptible of wide application and Ido not desire to be limited to the precise constructions nor set forth.

Having thus described my invention, I claim: I Y

1. A filter medium comprising a woven sheet having incorporated thereinmetallic fibers, said fibers. individually extending across only a partof said sheet.

2. A filter medium comprising a woven sheet including a metallic wool.

3. A filter medium comprising a Woven sheet including steel Wool.

4:. A filter medium comprising a woven to the specific materials sheet,one set of threads of which consists of metallic Wool.

5. A filter medium comprising a Woven sheet, one set of threads of whichconsists of steel wool. v

6. A filter medium comprising a woven sheet, one ply. of which consistsof aggregated metallic filaments. l

Witnesses 7. A filter medium comprising a woven sheet, one ply of whichconsists of matted aggregated metallic filaments.

8. A filter medium comprising a woven sheet, one set of threads of whichconsists of matted aggregated metallic filaments, and the other set ofwhich consists of metal strands.

9. A filter member including a central spacing member, a layer ofmetallic wool on either side thereof and a foraminous retaining memberfor holding each of said layers in place.

' 10. A filter member including a drainage member, a layer of metallicwool thereover 1 and a foraminous member for retaining said layer inplace.

ERNEST J. SWEETLAND.

GERALD E. TERWILLIGER, KARL S. DEITZ.

